To date, various devices have been proposed in our lives. While living among such devices, users enjoy desired information or services by manipulating the devices. Because of an increase in the number of devices themselves, an increase in the information that cannot be obtained without using devices, and so on, the importance of improving the manipulability of such interfaces is increasing year after year. In information devices (television sets, mobile phones, PDAs, etc.), for example, device manipulations are hitherto realized by selecting an manipulation option while watching a screen. As manipulation input means thereof, methods such as pressing a button, moving a cursor and making a confirmation, or manipulating a mouse while watching a screen have been used. However, it has often been impossible to execute a manipulation when both hands are unavailable, due to tasks other than device manipulations, e.g., household chores, rearing of children, and driving an automobile.
In answer thereto, there are input means utilizing biological signals from a user. Non-Patent Document 1 discloses a technique that utilizes an event-related potential of electroencephalograms for distinguishing an option which a user wishes to select. Specifically, options that a user wishes to select are randomly highlighted, and the waveform of an event-related potential which appears about 300 milliseconds after a point in time that an option was highlighted is utilized to enable distinction as to wishing to select or not. According to this technique, even in a situation where both hands are full, or even in a situation where the user is unable to move his or her limbs due to an illness or the like, the user can select an option which they wish to select, whereby an interface for device manipulations, etc., can be realized. Patent Document 1 also describes an example of a electroencephalograms interface which similarly uses an event-related potential.
Non-Patent Document 2 illustrates an application of a steady-state visual evoked potential (SSVEP), among other visual evoked potentials (VEPs). A steady-state visual evoked potential refers to a potential component which is superposed on a electroencephalogram signal when watching a light source that flickers with a constant frequency. It is known that, by subjecting the electroencephalogram signal to a frequency analysis, the same frequency as the flicker frequency of the light source appears in the electroencephalograms. In order to apply this mechanism to an electroencephalogram interface, with respect to a plurality of LEDs flickering at different frequencies, an evoked potential that occurs when a user watches a specific LED is caught in Non-Patent Document 2. With this evoked potential, it is identified that the specific LED has been selected, whereby one option can be selected from among as many options as there are LEDs.
Conventionally, a menu selection based on electroencephalograms has been realized by applying various processing to an electroencephalogram signal.
[Patent Document 1] Japanese Laid-Open Patent Publication No. 2004-275619
[Non-Patent Document 1] Donchinet al., “The Mental Prosthesis: Assessing the Speed of a P300-Based Brain-Computer Interface”, TRANSACTIONS ON REHABILITATION ENGINEERING 2000, Vol. 8, No. 2, June 2000
[Non-Patent Document 2] Xiaorong Gaoet al., “A BCI-Based Environment Controller for the Motion-Disabled”, IEEE Transactions on Neural Systems and Rehabilitation Engineering, Vol. 11, No. 2, June 2003